51吃瓜

In a sky so full of stars it鈥檚 often difficult to figure out where constellations are, one dark spot stands out: The Coalsack Nebula. Parked near one of the five brightest stars comprising the Southern Cross鈥攑erhaps the most easily spotted asterism in the southern sky鈥攖he nebula looks like an inky black thumbprint. Where it hangs, the stars struggle to shine. It鈥檚 as if someone outlined a portion of the sky and dimmed the lights.

Examples of confusing and misleading scientific terms abound. When astronomers say 鈥渕etals,鈥� they mean any element heavier than helium, which includes oxygen and nitrogen, a usage that is massively confusing not just to laypeople but also to chemists. The Big Dipper isn’t a constellation to them; it is an 鈥�asterism.鈥�

Many of the women (and a few men) were tourist attractions in their own right, with visitors flocking to the hotel as much to glimpse a quirky widow as to see the Pulitzer Fountain or to have a drink in the Oak Room. The Plaza staff grew accustomed to the widows鈥� peculiarities. One hotel manager began walking outside to get from one end of the building to the other, to avoid passing through the lobby, where persnickety widows would invariably be positioned on the divans, ready to greet him with a barrage of complaints.

[Prince] kept his cache of unreleased music locked in a vault beneath his Paisley Park complex in a suburb of Minneapolis. (The vault was a legend for years, until its existence was confirmed after Prince鈥檚 death.) In one story, the saxophonist Eric Leeds revealed that he had sequenced an entire album for Prince that was 鈥渢he greatest thing in the world in Prince鈥檚 mind鈥� for about three days. Then Prince got bored and shelved it. The vault is what remains of those myriad terminated sessions鈥攔emnants of the productive and exacting habits of a persnickety genius.

[H]yperspace was to be apprehended by the 鈥渕ental or inner eye鈥濃��.The ultimate vision, at least for the trainee, came with the apprehension of the hypercube or tesseract, which could be visualized through the manipulation of 鈥� cubes. One was to build a tesseract from an intricate arrangement of those cubes and then鈥攊n order to 鈥渟ee鈥� it鈥攑ass the tesseract through three-dimensional space. Just as a sphere passes through a plane in two-dimensional slices, so the tesseract would pass through three-dimensional space in three-dimensional slices.

The robot is building a tesseract. He motions at a glowing cube floating before him, and an identical cube emerges. He drags it to the left, but the two cubes stay connected, strung together by glowing lines radiating from their corners. The robot lowers its hands, and the cubes coalesce into a single shape鈥攚ith 24 square faces, 16 vertices, and eight connected cubes existing in four dimensions. A tesseract. This isn’t a video game. It’s a classroom. And the robot is Brian Greene, a physicist at Columbia University and bestselling author of several popular science books.